Four barrier removals, Danube River, Slovakia

Reconnecting the degraded Foki sidearm to the Danube River by removing four artificial barriers such as traverses and groynes.

Introduction

The Danube River, Europe’s second-largest river, flows through ten countries, supplying drinking water to 20 million people and connecting 83 million within its drainage basin. In Slovakia, the river transforms from a fast-flowing mountain stream to a slow-moving lowland river, depositing thick layers of sediment. This process has created the unique Danube inland delta, particularly in the region between Bratislava and Klížská Nemá. This area, with its main riverbed, side arms, islands, swamps, and meadows, was once rich and diverse, supporting various animal species.

However, 19th and 20th-century alterations, including the construction of the Gabčíkovo hydropower plant and artificial navigation channels, diverted water from the original riverbed. This significantly impacted the branch systems between Dobrohošť and Sap village, causing degradation over the decades. Despite these interventions, the area remains a vital ecosystem with a diverse wetland complex spanning over 4500 hectares, supporting a high degree of biodiversity.

At a glance

CountrySlovakia
RiverDanube
Km to be opened2,24
Focal speciesDanube rheophilic fish
Project typeDam removal (demolition)
Removal dateDecember 2023 - July 2024
Project statusLive

Project context and opportunity

Widespread infrastructure development along the Danube River has led to deteriorating water quality, reduced river dynamics, and significant biodiversity loss. The construction of hydroelectric power plants and navigation channels altered the river’s flow, converting many flowing sections into stagnant ones. Since 1992, up to 50% of Slovakia’s Danube habitats have been lost, particularly impacting the inland delta between Dobrohošť and Sap villages. Fish populations decreased by up to 70%, mainly due to inaccessible or degraded spawning grounds and lost dynamics.

The project’s primary objective is to restore a sidearm stream, “Foki,” by reconnecting it to the main riverbed, reviving the natural water regime and dynamics. This restoration will have gradual and far-reaching effects, benefiting Danube habitats, including breeding and feeding areas for endangered species. It will also enhance groundwater levels, water retention, and flood protection while aiding native fish populations and alluvial forests.

Project aims

This project aims to restore a section of the Danube by reconnecting the degraded Foki sidearm to the Danube, removing four artificial barriers such as traverses and groynes. Removing the structures will allow year-round access to the mainstem, a unique feature in Slovakia. This project aligns with the Ramsar Convention, Water Framework Directive, Slovak Water Strategy, and EU Biodiversity Strategy 2020 by implementing conservation measures outlined in existing management plans, emphasising the importance of preserving this vital ecosystem.

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